Spectroscopic Signatures of Structural Disorder and Electron-Phonon Interactions in Trigonal Selenium Thin Films for Solar Energy Harvesting

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Main Authors: Nielsen, Rasmus S., Medaille, Axel G., Torrens, Arnau, Segura-Blanch, Oriol, Kavanagh, Seán R., Scanlon, David O., Walsh, Aron, Saucedo, Edgardo, Placidi, Marcel, Dimitrievska, Mirjana
Format: Preprint
Published: 2025
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author Nielsen, Rasmus S.
Medaille, Axel G.
Torrens, Arnau
Segura-Blanch, Oriol
Kavanagh, Seán R.
Scanlon, David O.
Walsh, Aron
Saucedo, Edgardo
Placidi, Marcel
Dimitrievska, Mirjana
author_facet Nielsen, Rasmus S.
Medaille, Axel G.
Torrens, Arnau
Segura-Blanch, Oriol
Kavanagh, Seán R.
Scanlon, David O.
Walsh, Aron
Saucedo, Edgardo
Placidi, Marcel
Dimitrievska, Mirjana
contents Selenium is experiencing renewed interest as a elemental semiconductor for a range of optoelectronic and energy applications due to its irresistibly simple composition and favorable wide bandgap. However, its high volatility and low radiative efficiency make it challenging to assess structural and optoelectronic quality, calling for advanced, non-destructive characterization methods. In this work, we employ a closed-space encapsulation strategy to prevent degradation during measurement and enable sensitive probing of vibrational and optoelectronic properties. Using temperature-dependent Raman and photoluminescence spectroscopy, we investigate grown-in stress, vibrational dynamics, and electron-phonon interactions in selenium thin films synthesized under nominally identical conditions across different laboratories. Our results reveal that short-range structural disorder is not intrinsic to the material, but highly sensitive to subtle processing variations, which strongly influence electron-phonon coupling and non-radiative recombination. We find that such structural disorder and grown-in stress likely promote the formation of extended defects, which act as dominant non-radiative recombination centers limiting carrier lifetime and open-circuit voltage in photovoltaic devices. These findings demonstrate that the optoelectronic quality of selenium thin films can be significantly improved through precise control of synthesis and post-deposition treatments, outlining a clear pathway toward optimizing selenium-based thin film technologies through targeted control of crystallization dynamics and microstructural disorder.
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id arxiv_https___arxiv_org_abs_2507_23647
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectroscopic Signatures of Structural Disorder and Electron-Phonon Interactions in Trigonal Selenium Thin Films for Solar Energy Harvesting
Nielsen, Rasmus S.
Medaille, Axel G.
Torrens, Arnau
Segura-Blanch, Oriol
Kavanagh, Seán R.
Scanlon, David O.
Walsh, Aron
Saucedo, Edgardo
Placidi, Marcel
Dimitrievska, Mirjana
Materials Science
Selenium is experiencing renewed interest as a elemental semiconductor for a range of optoelectronic and energy applications due to its irresistibly simple composition and favorable wide bandgap. However, its high volatility and low radiative efficiency make it challenging to assess structural and optoelectronic quality, calling for advanced, non-destructive characterization methods. In this work, we employ a closed-space encapsulation strategy to prevent degradation during measurement and enable sensitive probing of vibrational and optoelectronic properties. Using temperature-dependent Raman and photoluminescence spectroscopy, we investigate grown-in stress, vibrational dynamics, and electron-phonon interactions in selenium thin films synthesized under nominally identical conditions across different laboratories. Our results reveal that short-range structural disorder is not intrinsic to the material, but highly sensitive to subtle processing variations, which strongly influence electron-phonon coupling and non-radiative recombination. We find that such structural disorder and grown-in stress likely promote the formation of extended defects, which act as dominant non-radiative recombination centers limiting carrier lifetime and open-circuit voltage in photovoltaic devices. These findings demonstrate that the optoelectronic quality of selenium thin films can be significantly improved through precise control of synthesis and post-deposition treatments, outlining a clear pathway toward optimizing selenium-based thin film technologies through targeted control of crystallization dynamics and microstructural disorder.
title Spectroscopic Signatures of Structural Disorder and Electron-Phonon Interactions in Trigonal Selenium Thin Films for Solar Energy Harvesting
topic Materials Science
url https://arxiv.org/abs/2507.23647